Pro bike: Retro Specialized Rock Combo and custom painted Unbound Gravel Diverge

In the beginning, there was nothing and then Specialized said, ‘let there be gravel bikes’ and there was the Rock Combo. A bike that blended two polarising ends of the cycling spectrum and was hailed by Ned Overend as a bike that could 'truly go anywhere and do anything'. Unfortunately for Specialized, 1989 wasn’t ready for such a bike and following low sales, Specialized canned the Rock Combo the following year.

“Then we had the RockCombo. Some really loved it but some others really questioned why we’d developed a bike that could go on and off-road. We felt it worked well, and the drop bars, which are great for handling and power gave riders an option but ultimately the bike wasn’t successful. People were so into the mountain bike that they questioned what we were doing and it wasn’t either fish or meat, so they just didn’t like it. We still loved it though and felt that it was super efficient." explained Mike Sinyard, the founder and CEO of Specialized, when we caught up a few months ago.  

On- and off-road hybrids weren’t anything new even then but they were just mutated mountain bikes with skinny tires. Where the Rock Combo differed was that it was designed from the ground up and unbeknownst to Specialized, would be the genesis of the gravel bike some 25 years later. 

Built from triple-butted Chromoly steel, Specialized reworked the Stumpjumper geometry, steepening the head angle by a degree and lengthening out the chainstays to make it work better with the drop bars. The bars themselves were new Specialized ATB drop bars which measured 44cm wide and flared out to 55cm at the ends for better off-road control. You would need that extra control as well, while the geometry is surprisingly relevant even by today’s standards, componentry has come a long way in the last 25 years. Specialized specced a Suntour groupset with bar-end shifters. The triple chainset came with 28/38/48 chainrings and the seven-speed cassette had a spread of 13-30. The brakes were Dia Compe 984D cantilever brakes paired with SunTour GPXBRS aero levers, which after reading Guy Kesteven’s recent Bespoken Word: Braking bad article, I can only assume worked terribly. The wheels paired Specialized GX-23 26in rims with 32 hole SunTour XCD-6000 quick-release hubs which used Specialized HardPack tires in a 1.5in size - or 28mm as we would know it. Finishing the bike was a Selle Italia Turbo saddle in black leather. All in the bike weighed around 13kg.

It wasn’t until the launch of the Diverge in 2014 that Specialized truly returned to the world of gravel. The Diverge is at the forefront of gravel tech setting the benchmark of tire clearance, gravel geometry and innovative tech in the form of FutureShock suspension and SWAT storage. While the Rock Combo geometry wasn’t too far off, Specialized has had plenty of time to make some refinements for the Diverge. The reach is a little shorter as are the chainstays and wheelbase, the head angle is a touch slacker and the seat angle half a degree steeper. 

Luckily for Alison Tetrick, Ian Boswell, and Laurens ten Dam who will be racing the Specialized Diverge at this weekend's Unbound Gravel event, there are significant differences between the two bikes.

Specialized uses its FACT 11r carbon for the frame and fork which Specialized claims weigh under a kilo. The frameset features internal routing, SWAT storage within the downtube and Future Shock 2.0 suspension for added control and comfort after miles of gravel roads or it can be locked out for smooth road sections.

Despite only having a single front chainring, SRAM’s Red Eagle groupset with a 42T chainring and 10-50 cassette manages to give a wider spread of gears than Rock Combo, not forgetting that the clutched derailleur makes dropped chains a rarity and the wireless electronic shifting would have seemed like something out of science fiction back in 1989.

Braking is equally revolutionary thanks to the stopping power and all-weather reliability that is brought with disc brakes. SRAM Red disc brakes are paired with 160mm rotors front and rear.

Modern gravel bikes were thankfully unafflicted by the 26in wheel and the Unbound Gravel Diverge’s will be using carbon wheels from Roval and fitted with Specialized Pathfinder Pro gravel tires. Thankfully the hideous Specialized MTB3 quill stem of the Rock Combo is a thing of the past, instead, the Diverge is tastefully kitted out with a Zipp Service Course SL finishing kit.

Arguably the best bit of the Rock Combo has been remembered, the strong 80’s aesthetic lives on through these custom painted Diverge’s which commemorate the Rock Combo at this year's Unbound Gravel event. Specialized has done an excellent job of capturing the original design and transposing it onto the new bike to bring the retro vibe and a reminder of gravel's roots to the dirt roads of Kansas.

Tech Specs: Specialized Rock Combo

  • Frame: Specialized Rock Combo
  • Fork: Specialized Unicrown
  • Groupset: SunTour XCD-6000 with ST-2 crankset
  • Brakes: Dia-Compe 984D
  • Wheelset: Specialized GX-23 and SunTour XCD-6000 hubs
  • Stem: Specialized MTB-3
  • Handlebars: Specialized ATB drop bar
  • Seatpost: Strong
  • Saddle: Selle Italia Turbo
  • Pedals: SR MTP-126
  • Tires: Specialized Hardpack 1.5in
  • Computer: What's a computer?

Tech Specs: Specialized Diverge Unbound Gravel custom

  • Frame: Specialized Diverge S-Works
  • Fork: Specialized Future Shock 2.0
  • Groupset: SRAM Red
  • Brakes: SRAM Red
  • Wheelset: Roval
  • Stem: Zipp Service Course SL
  • Handlebars: Zipp Service Course SL
  • Seatpost: Zipp SL Speed
  • Saddle: Specialized Power with Mirror
  • Pedals: Time
  • Tires: Specialized Pathfinder Pro
  • Computer: Lezyne
Graham Cottingham
Senior reviews writer, Bike Perfect

Graham is all about riding bikes off-road, based in Edinburgh he has some of the best mountain biking and gravel riding in the UK on his doorstep. With almost 20 years of riding experience, he has dabbled in downhill, enduro, and gravel racing. Not afraid of a challenge, Graham has embraced bikepacking over the last few years and likes nothing more than strapping some bags to his bike and covering big miles to explore Scotland's wildernesses. When he isn’t shredding the gnar in the Tweed Valley, sleeping in bushes, or tinkering with bikes, he is writing tech reviews for Bike Perfect.

Rides: Cotic SolarisMax, Stooge MK4, 24 Bicycles Le Toy 3, Surly Steamroller

Height: 177cm

Weight: 71kg